Peppermint plant named ‘Pranjal’

ABSTRACT

Described as a new Peppermint mutant having a high yield of menthol rich essential oil, deep purplish green foliage, purplish white flowers, a delayed temporary wilting point and tolerance to the pest Bihar hairy caterpillar ( Spilarctia obliqua ).

Latin name of genus and species: The present invention relates to a newMentha×piperita plant.

Variety denomination: The new Mentha×piperita plant has the varietaldenomination ‘Pranjal’.

BACKGROUND OF THE INVENTION

In order to overcome a major bottleneck encountered in the cultivationof peppermint (Mentha×piperita), which is low oil yielding coupled withsusceptibility to Spilarctia obliqua (Bihar hairy caterpillar), aplanned breeding program was initiated. The commercial cultivation ofMentha×piperita is widely spread in tropical and subtropical climatesand its oil finds widespread use in flavoring, cosmetics andpharmaceutical industries. As the Mentha×piperita is infertile or littlefertile in nature, mutagen treatment and induced ploidy is the mostappropriate way to create new genetic variability. Screening of thedesired altered genotype is the most important step as most of theinduced mutations are deleterious and undesirable. Accordingly, in orderto develop a peppermint plant capable of yielding high levels of mentholoil and being resistant to Bihar hairy caterpillar, a planned breedingprogram was undertaken. The program resulted in a genotype CIMAP/MPP-4having the varietal denomination ‘Pranjal’. This plant of the inventionrepresents induced genetic variability followed by selection forimprovement in terms of high oil yield, high menthol content andenhanced level of tolerance towards a common pest (Bihar hairycaterpillar i.e. Spilarctia obliqua).

SUMMARY OF THE INVENTION

The present invention relates to a genotype of Mentha×piperita named‘Pranjal’ and belonging to family Lamiaceae. The new variety is amutant, developed in a breeding program for resistance to the Biharhairy caterpillar (Spilarctia obliqua) with emphasis on essential oilhaving high menthol content. The Mentha×piperita parent cultivars arenon-patented. A locally adopted strain (non-patented) was used for theplanned induced mutagenesis experiment.

‘Pranjal’ is propagated vegetatively through suckers and hence can bemaintained as a stable genotype. The plant is a perennial, glabrous andaromatic herb widely cultivated for its essential oil which is ofcommercial and export value. The following description is of plantsgrown in Uttar Pradesh, India. The plants as described are 80 to 100days after transplantation of suckers. Color descriptions are inaccordance withThe Royal Horticultural Society (R.H.S.) Colour Chart.

BRIEF DESCRIPTION OF ILLUSTRATIONS

The accompanying illustrations depict specimen plants of the new varietyin color as true as possible in color photographic illustrations of thisnature.

FIG. 1 represents twigs of the new variety;

FIG. 2 represents colonies of the new variety; and

FIG. 3 represents the typical RAPD profile of the new variety. Lane 1: λHindIII marker. Lanes 2-20: RAPD profiles with the following primers:

Lane 2 AAATCGGAGC SEQ. ID NO. 1 Lane 3 TGCGCGATCG SEQ. ID NO. 4 Lane 4CTATCGCCGC SEQ. ID NO. 7 Lane 5 CCCTGCAGGC SEQ. ID NO. 10 Lane 6AGGATACGTG SEQ. ID NO. 13 Lane 7 TTGTCTCAGG SEQ. ID NO. 16 Lane 8AGCCTGACGC SEQ. ID NO. 19 Lane 9 GTCCTACTCG SEQ. ID NO. 2 Lane 10AACGTACGCG SEQ. ID NO. 5 Lane 11 CGGGATCCGC SEQ. ID NO. 8 Lane 12CCAAGCTTGC SEQ. ID NO. 11 Lane 13 AAGATAGCGG SEQ. ID NO. 14 Lane 14CATCCCGAAC SEQ. ID NO. 17 Lane 15 GTCCTTAGCG SEQ. ID NO. 3 Lane 16GCACGCCGGA SEQ. ID NO. 6 Lane 17 GCGAATTCCG SEQ. ID NO. 9 Lane 18GTGCAATGAG SEQ. ID NO. 12 Lane 19 GGATCTGAAC SEQ. ID NO. 15 Lane 20GGACTCCACG SEQ. ID NO. 18

DESCRIPTION OF THE NEW VARIETY

The girth of the stem of the new variety is between about 1.0 and 2.0 cmgirth and typically high pigmentation to serve as a characteristicmarker (FIG. 1). The main axis possesses between 15 and 20 nodes withinternodes between about 2.5 and 3.0 cm. As seen in FIG. 1, the stem ismarked by reddish purple pigmentation; the color generally varies frombetween 61A to 59B (red purple) on The R.H.S. Colour Chart. As seen inFIGS. 1 and 2, the leaves are found to be of green color, whichcorresponds to near 146A (green) on The R.H.S. Colour Chart. The leavesand the foliage as such, are marked by reddish purple pigmentation,corresponding to color code near 61A on The R.H.S. Colour Chart. Leavesare also highly pigmented and ovate. Leaf area ranges from between about5.5 and 6.0 cm². Fresh herb yield is between 15 and 20 T/ha with oilyield between about 140.0 and 150.0 1/ha of oil. Major oil componentsdetected are menthol, menthone, neo-menthone, menthyl acetate andisomenthone and are in the range of between about 50% and 55%, 12% and14%, 5% and 8%, 4% and 6% and 3% and 4% respectively. The propagatedpopulation of ‘Pranjal’ is uniform and can be harvested after about 80to 100 days of sucker transplantation and performs best at about 60 cminter-row spacing.

‘Pranjal’ (CIMAP/MPP-4) is thus a new and distinct variety ofMentha×piperita having the following combination of characters:

(a) deep purplish green foliage and purplish white flowers;

(b) although seed set occurs, seeds are not viable;

(c) tolerance to Bihar hairy caterpillar (about 30% infestation observedunder natural epiphytotic conditions); and

(d) stable high oil yields with relatively high content of menthol.

The new variety:

i) has an average of about 40 leaves on its main axis, as compared to 23found in the control plant ‘Kukrail’ (non-patented);

ii) has average leaf-stem ratio of about 0.36 which is much higher thanthe control plant ‘Kukrail’. The leaf-stem ratio in the control plant isabout 0.26;

iii) exhibits menthol content of about 51.59% in the essential oil ascompared to 27.46% in the control plant ‘Kukrail’. The oil profile ofthe new variety shows its constituents as menthone, neo-menthone,menthyl acetate and isomenthone;

iv) provides total oil yield per hectare of about 145.45 as compared to72.72 1/ha of the control plant ‘Kukrail’;

v) exhibits greater tolerance (up to about 30%) infestation to the Biharhairy caterpillar under epiphytotic conditions as compared to thecontrol plant ‘Kukrail’ (about 70% infestation); and

vi) shows temporary willing point (TWP) as compared to the controlplant.

The new genotype of the new variety was developed through plannedmutational breeding experiments conducted at Central Institute ofMedicinal and Aromatic Plants (CIMAP) , Lucknow, India with defined aimto develop superior genotype possessing high oil content with improvedoil quality and tolerance to Bihar hairy caterpillar. For this purpose,2 inch pieces of suckers of locally grown cultivator of PantnagarMentha×piperita were given 3 treatments (1.5 kR, 3.0 kR, .4.5kR) of−radiation. The irradiated suckers were transplanted in a field withinter-row spacing of 60 cm and 4′ distance within a row (FIG. 2) alongwith control plants. Plants which are not subject to mutagenic treatmentare herein referred as ‘controls’. The control plant used in the instantinvention was ‘Kukrail’. Data was recorded for various qualitative andquantitative traits including oil yield and composition. Selection wasmade on the basis of vigorous plant growth coupled with high oil yieldwith good quality oil profile. The selected variant was multiplied,tested for homogeneity in the population and further evaluated forperformance in M2 through M5 generations.

Considering the variation in morphometric traits, 13 variants wereselected from the irradiated plants. These selected variants weremultiplied by transplanting the stolons again at 4′ distance within arow in order to purify the variant genotypes to homogeneity in the M2generation and 10 clones with variable morpho-metric characteristicswere screened. These clones were grown in replicated trials in M3 and M4generations in 3 meter rows along with parent and cv. Kukrail followinguniform cultural practices to study oil yield and pest tolerance. Out ofthe 10 clones, 7 performed better than the parent in terms of oil yield.Among the seven, three clones showed better tolerance towards Biharhairy caterpillar and one among the three was even superior in terms ofrelatively high content of menthol. This plant bearing number CIMAP/MPP4in the breeding program was finally christened as ‘Pranjal’.

The new variety ‘Pranjal’ was moderate in height and canopy but wasfound vigorous as it possessed more number of leaves on its main axisand had greater leaf-stem ratio in comparison to both the parent and cv.Kukrail. The new variety maintained its superior performance over parentand cv. Kukrail in M3 and M4 generations. This plant yielded 145.45 1/haof oil in comparison to 72.72 1/ha produced by the control plants andwas superior in terms of menthol content (51.59% in comparison to 27.46%in control plants).

‘PRANJAL’ TRAIT 1998 1999 2000 Plant Height (cm) 48 48 46 Canopy (cm) 4142 43 Stem Girth (cm) 1.6 1.5 1.6 Nodes/main axis 19 18 20 AverageInternode length (cm) 2.9 2.8 2.8 Number of main branches 36 36 36 Leafstem ratio 0.34 0.36 0.39 Leaves on main axis 40 40 40 Leaf area (cm²)5.9 5.8 5.8 Herb Yield (T/ha) 19 18.2 18 Oil Content (% V/W) 0.8 0.8 0.7Menthol (% V/V) 52 51.6 52 Menthone 15.7 13.6 12.2 Neo-menthone 6.156.16 6.64 Menthyl acetate 5.61 5.44 4.63 Iso-menthone 3.74 4.02 4.02Total oil yield (1 ha) 141.9 144.39 144.4

Comparison variety:

‘Kukrail’ TRAIT 1998 1999 2000 Plant Height (cm) 52 52 51 Canopy (cm) 5252 54 Stem Girth (cm) 1.9 1.7 1.7 Nodes/main axis 17 18 17 AverageInternode length (cm) 2.5 2.6 2.5 Number of main branches 34 37 37 Leafstem ratio 0.22 0.26 0.26 Leaves on main axis 25 23 22 Leaf area (cm²)5.6 5.8 5.6 Herb Yield (T/ha) 18 18.2 19 Oil Content (% V/W) 0.5 0.450.47 Menthol (% V/V) 27.8 27.5 28.3 Menthone 22.7 23.9 22.8 Neo-menthone3.4 3.26 3.46 Menthyl acetate 2.59 2.52 2.74 Iso-menthone 5.12 4.48 4.58Total oil yield (1 ha) 90 72.72 89.3

Comparison of varieties ‘Pranjal’ versus ‘Kukrail’ using the followingdefinitions:

TRAIT SEM CD (1%) CD (3%) Plant Height (cm) 1.67 7.46 5.25 Canopy (cm) 14.49 3.16 Stem Girth (cm) 0.098 0.44 0.31 Nodes main axis 0.53 2.36 1.66Average Internode length (cm) 0.085 0.38 0.27 Number of main branches0.95 4.25 2.99 Leaf stem ratio 0.007 0.33 0.23 Leaves on main axis 0.883.94 2.77 Leaf area (cm²) 0.11 0.48 0.34 Herb Yield (T ha) 0.38 1.71 1.2Oil Content (% V W) 0.034 0.15 0.11 Menthol (% V V) 1.07 4.8 3.38Menthone 0.84 3.78 2.66 Neo-menthone 0.32 1.45 1.02 Menthyl acetate 0.31.35 0.95 Iso-menthone 0.28 1.27 0.9 Total oil yield (1 ha) 1.24 5.573.92 SEM = Standard Error of Mean CD (1%) = critical difference at 1%probability level CD (5%) = critical difference at 5% probability level

Thus, the new variety ‘Pranjal’ (CIMAP/MPP-4) is a selection from clonedpopulation of Mentha×piperita and is characterized as a perennial,glabrous herb of 45-50 cm height having canopy 40-45 cm.

The following is an objective description of the new variety.

Genus: Mentha.

Species: Piperita.

Family: Lamiaceae.

Common name: Peppermint.

Plant height: About 50 cm.

Growth habit: Herb with slender creeping rootstocks sending up erectpurple branches.

Stem: Red purple near (59A), quadrangular, girth about — 1.5 cm.

Leaf: Simple, Yellow green near (147A).

Texture: Soft Leather.

Surface: Rough due to sparse trichomes.

Shape: Ovate.

Margin: Serrated.

Tip: Acute.

Base: Tapering (Acute).

Size: Broad.

Length: About 5.5 cm.

Width: About 2.6 cm.

Petiole length: About 0.8 cm.

Area: About 5.8 cm².

Leaf-stem ratio: About 0.36.

Inflorescence:

Form.—Verticillaster.

First flowering.—Approximately the last week of July when transplantedin about the first week of February (165 days).

Flower.—Near purple white; diameter about 0.6 cm; mild fragrance.

Pedicel.—Color near 189A; length about 0.4 cm.

Calyx.—Near Yellow green (near 144A); diameter about 0.4 cm.

Corolla.—Near white (near 155C).

Anthers.—About four — near purple (near 184A) — rudimentary, remaininginside corolla tube.

Stigma.—Bifid, color near 155B.

Ovary.—Color near 138B.

Percent of oil content in fresh herb: About 0.8%.

Oil quality:

Menthol content (%).—About 51.59%.

Menthone content(%).—About 13.57%.

Neo-menthone content (%).—About 6.16%.

Menthyl acetate (%).—5.44%.

Iso-menthone (%).—3.08%.

RAPD profile (FIG. 3)

The flowers of ‘Pranjal’ do not set seed at Lucknow, India; accordingly,no dimensions are available. The plant has been reproduced asexuallythrough suckers.

EVIDENCE OF UNIFORMITY AND STABILITY

The new variety (genotype CIMAP/MPP-4) has remained stable and uniformfor its morphometric traits and showed consistent performance for oilyield and quality during its evaluation and multiplication in the years1998 and 1999.

DELAYED TEMPORARY WILTING POINT

To assess the new variety for its hardiness an experiment was carriedout to know the delayed temporary wilting point under controlledenvironmental conditions using both ‘Pranjal’ and control ‘Kukrail’. Ten(10) cm long twigs (3 replications, 10 twigs each) were kept with theircut end dipped in sterile water in a test tube for 4 weeks at 30° C. Thefollowing table represents the percentage of wilting tabulated at theend of the month in the two genotypes (‘Pranjal’ and ‘Kukrail’) after 30days:

S1. No. Genotype Percentage of wilting 1. ‘PRANJAL’ 3.3% 2. ‘Kukrail’90.0%

The new variety was tested for its tolerance to Bihar hairy caterpillar(Spilarctia obliqua). Studies on the plant in the years 1998, 1999 and2000 revealed that the plant is highly tolerant to this infestation. Theresults are depicted here below:

Percentage of infestation in the year Genotype 1998 1999 2000 ‘PRANJAL’9.9 8.3 8.6 (CIMAP/MPP-4) ‘Kukrail’ 45.5 56.3 64.3 CD 4.5 5.2 3.6

These values are based on observations recorded on 10 plants ach inthree (3) replications over three (3) years.

Hence, ‘Pranjal’ has shown tolerance to this pest in comparison to‘Kukrail’, the control plant.

19 1 10 DNA Artificial Sequence Oligonucleotide primer for RAPD profile1 aaatcggagc 10 2 10 DNA Artificial Sequence Oligonucleotide primer forRAPD profile 2 gtcctactcg 10 3 10 DNA Artificial SequenceOligonucleotide primer for RAPD profile 3 gtccttagcg 10 4 10 DNAArtificial Sequence Oligonucleotide primer for RAPD profile 4 tgcgcgatcg10 5 10 DNA Artificial Sequence Oligonucleotide primer for RAPD profile5 aacgtacgcg 10 6 10 DNA Artificial Sequence Oligonucleotide primer forRAPD profile 6 gcacgccgga 10 7 10 DNA Artificial SequenceOligonucleotide primer for RAPD profile 7 ctatcgccgc 10 8 10 DNAArtificial Sequence Oligonucleotide primer for RAPD profile 8 cgggatccgc10 9 10 DNA Artificial Sequence Oligonucleotide primer for RAPD profile9 gcgaattccg 10 10 10 DNA Artificial Sequence Oligonucleotide primer forRAPD profile 10 ccctgcaggc 10 11 10 DNA Artificial SequenceOligonucleotide primer for RAPD profile 11 ccaagcttgc 10 12 10 DNAArtificial Sequence Oligonucleotide primer for RAPD profile 12gtgcaatgag 10 13 10 DNA Artificial Sequence Oligonucleotide primer forRAPD profile 13 aggatacgtg 10 14 10 DNA Artificial SequenceOligonucleotide primer for RAPD profile 14 aagatagcgg 10 15 10 DNAArtificial Sequence Oligonucleotide primer for RAPD profile 15ggatctgaac 10 16 10 DNA Artificial Sequence Oligonucleotide primer forRAPD profile 16 ttgtctcagg 10 17 10 DNA Artificial SequenceOligonucleotide primer for RAPD profile 17 catcccgaac 10 18 10 DNAArtificial Sequence Oligonucleotide primer for RAPD profile 18ggactccacg 10 19 10 DNA Artificial Sequence Oligonucleotide primer forRAPD profile 19 agcctgacgc 10

We claim:
 1. A new and distinct Peppermint plant named ‘Pranjal’ of thevariety substantially as shown and described.